Precipitating bath for making threads or the like from viscose



Patented July 26, 1932 UNITED STATES PATENT orriee ADOLF IKi'lIlVlIIEIB, OF DESSAU-ZIEBIGK, GERMANY, ASSIGNOR TO I. G. FARBENINDUSTR-IE AK'IIENGESELLSCHAFT, OF FRANKFORT-ON-THE-IIAIN, GERMANY, A CORPORATION OF GERMANY PRECIPITATING- BATH FOR MAKING THREADS OR THE LIKE FROM VISGOSE No Drawing. Application filed December 28, 1928, Serial No. 329,073, and in Germany January 5, 1928.

The result is not a mere proportional effect,

but is specific to the labile condition produced by the state of saturation. This is evidenced by the fact that the said state of saturation maybe due to the amount of the organic substance' 'present per se in the bath, or to the amount of the organic substance in addition'to the inorganic electrolytes (acid and salts), present, in which case the percentage of the organic substance in the bath is considerably less, since the saturation state is affected by the electrolytes.

Thus it happens that with a higher concentration of acid and a smaller addition of added'substance, better effects are produced on the formation of the thread than is the case with a lower acid concentration and higher addition.

The following comparison will illustrate this A spinning bath which contains 15 per cent. of sulphuric acid, 17 per cent. of sodium sulfate, and such a proportion of an added substance sufficient for yielding threads which are of high luster, suffers in its good properties more or less quickly as the acid content is moderately increased, since the threads, as the content of acid rises, are more and more penetrated with bubbles which affeet the physical properties and the appearance of the thread.

If, however, the acid content of the same bath is increased to a greater extent, for example to 4.2 per cent. the amount of sodium sulfate and organic addition which can be taken up by the bath is much smaller and amounts for example to only a small percentage of the quantity of acid. In spite of this, however, it is possible in a bath of such acid content to spin quite homogeneous threads of finest titer and free from included gas, and therefore very strong and lustrous, particularly when completely non-matured viscose is used.

The effect of the added organic substance is due to the formation of an adsorbed layer of the substance on the viscose threads, which layer protects the thread more or less from the weakening effect of the electrolyte. This protective layer becomes apparent when using carbazolsulfonic acid from the strong color effect of the precipitating bath on the fiber. Owing to their high tensile strength, the threads made by aid of baths according to this invention are remarkably suitable for being dyed black and for weaving silk.

The following examples illustrate the invention, the parts being by Weight:

Emam-pe 1.Unmatured viscose of 5 per cent. strength and of a temperature of 9 C. is squirted into a spinning bath having a temperature of 13 C. and containing 37.5 per cent. of the artificial tanning agent being the condensation product of napthalene sulfonic acid with formaldehyde. The individual titer is 1.4 denier, the length of immersion centimeters, and the length of the path in air is 110 centimeters; the total acidity of the bath is 12 per cent calculated as sulfuric acid. The artificial silk threads produced, which are finished by the usual treatment, have a tensile strength of about 2.5 grams per denier with an extensibility of about 7 per cent.

Emample Z.Artificial silk is produced under the conditions described in Example 1, but by means of a precipitating bath which contains 66 parts of water 25 parts of sodium carbazolesulfonate and 9 parts of sulfuric acid. In this spinning bath threads are ob tained having a tensile strength of 2.65 grams per denier and an extensibilityof about 10 per cent. The threads are dyed a pronounced violet-brown.

Emample 5.Viscose of no degree of maturity is squirted through nozzles of 0.1 millimeter internal diameter into a bath which contains 35 per cent. sulfuric acid and 5 per cent. of sodium carbazolesulfonate. The

temperature of the bath is 13 (1, the length of immersion 20 centimeters, and the rate of 5 spinning 25 meters per minute; the wound spools are treated in a topping bath with sulfuric acid of 14.5 per cent. strength at a temperature of 6 C.

Emample 4.The same effect is produced by a bath containing 42 per cent. of sulfuric acid and 4 per cent. of sodium carbazolesulfonate. The temperature is 9 C. and the other conditions are those stated in Example 1.

Example 5.A spinning bath is used which contains 42 per cent. of sulfuric acid and 2 per cent. of the product of reaction of formaldehyde on napthalene-sulfonic acid; the temperature is 6 C., the length of immersion 20 centimeters, the strength of the topping bath 14.5 per cent. of sulfuric acid and thetemperature' of the topping bath 5 The spinning baths specified in the preceding examples may contain an addition of 2'per cent. of sodium sulfate, and with or Without this addition and also without the use of the topping bath, give good results. In. all the examples the temperature of the iscose is 9 C. In each case strongand lustrous threads having good textile qualities are obtained. In using the percipitating baths according to this invention, particularly low temperatures, especially under 15 C. and also below 0 6., are of specially favorable effect.

The spinning baths according to the invention differ from those hitherto known also in the fact that. by use of the additions an acid content exceeding 25 per cent. calculated as sulfuric acid may be used.

My invention is not limited to the foregoing examples or to the specific details given therein. Various modifications and changes in details and the use of equivalents of the compounds of high molecular weight enu-' merated in the foregoingexamples are considered to be within the spirit of the invention and the scope of the following claims. Having thus described the nature of the said invention and the best means I know of carrying the same into practical effect, I claim zl 1. A process of spinning threads,,bands, films and the like from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a spinning bath containing, in a state of substantial saturation, an organic compound of high molecular weight soluble in the usual acid precipitating .baths and being a tanning agent of the group consisting of carbazole sulfonic acid and formaldehyde naphthalene sulfonic acid con- F densation products. 2. A process of producing threads, bands,

films, from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a coagulating bath containing, in a state of substantial saturation, sodium carbazolesulfonate.

3. Aprocess of producing threads, bands, films from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a coagulating bath containing acid not less than25 per cent, calculated as sulfonic acid, and, in a state of supstantial saturation, an organic compound of high molecular weight soluble in the usual acid precipitating baths, of the group consisting of carbazole sulfonic acid and formaldehyde naphthalene sulfonic acid condensation products.

4. A process of producing threads,bands, films from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a coagulating bath containing acid not less than 25 per cent, calculated as sulfonic acid, and, in 'a state of substantial saturation, sodium carbazolesulfonate.

5. A process of producing threads, bands, films from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a coagulating bath containing not less than 25 percent. of sulfuric acid and, in a state of substantial saturation, an organic-compound of high molecular weight soluble in the usual acid precipitating baths, of the group consisting of carbazole sulfonic acid and formaldehyde naphthalene sulfonic acid condensation products.

a 6. A process of producing threads, bands, films from viscose, particularly unmatured viscose, which comprises the step of squirting the viscose into a coagulating bath containing not less than 25 per cent. of sulfuric acid and, in a state of substantial saturation, sodium carbazolesulfonate.

In testimony whereof, I afiixmy signature.

DR, ADOLF KAMPF. 

